Mercurial printing surface



April 3, I192s. 1,665,000

A. R. TRlsT MERCURIAL PRINTING SURFACE Filed oct. 5. 1926 Patente pr. 3, 1928n ED STATES Airman' RONALD rarer, or Lennon, mvsnmvn.

MERCURIAL PRINTEN@ SURFCE.

'PATENT Application lcdpctober 5, 1926, Serial. No. 139,651, and in Great britain November 5, 1925.

'lhis invention relates to improvements in mercurial printing surfaces and has for its object the production of a truly planographicsurface of this type With greater ease and reliability by comparatively unskilled operators than khas been possible heretofore.

ln my British specification No. 225,928 a process by Which a truly planographic printing surface can be produced has been *fully described, said planographic printing surface comprising printing areas and recesses filled with a composition of copper, silver or gold and mercury prepared by electrodepositing a very thin layer of copper into the recesses in the plate, then a very,

thin layer of silver or gold on to the copper and so on until the recesses are filled up. The reason for adopting this method of producing the mercurial composition was ,to enable said composition to have some of the characteristics of both copper and silver or gold amalgams and to be of a firmly adherent nature. The metal of which' this printing late was made was defined as being una eoted by mercury and nickel was referred to by Way ot example. lin the industrial manufacture of such a plate diiificulties have been encountered inasmuch as it has |been found that the presence of the smallest quantity of foreign matter or oxide remaining on thenickel prevents that intimate adhesion oilthe initlal layer of copper to the nickel which is necessary to maintain the la ers in place after they have been treate with mercury.

Experiments have shown that the alternate layers of copper and silver or gold prevent diflusion of the mercury from the amalgam to such a degree as to render unnecessary the use of a metal una ected by mercury for supporting the amalgam in place; further it liasbeen 'found that small traces of etching iiuid on a copper surface do not have such'a deleterious effect on the linal result as when nickel is employed and although cleanliness is of importance, that cleanliness which is readily obtainable/inl 'an ordinary Worksho by an average artisan is sudicient to o tain reliable and satisfactory printing plates to be obtained.

This invention consists in 'the formation oit a planographic printing plate having ink "retaining areas and mercurial ink refusing areas, comprising an eleetrodeposited layer of metal with which mercury can amalga' mate, an electrodeposited layer of a metal unaffected by mercury to which printing ink will adhere, recesses in such last named layer locally exposing the first named layer, said recesses being filled with a plurality of alternately electrodeposited films of two metals one ot which forms a hard amalgam with mercury, Whilst the other takes a high polish when treated With mercury, a film of the last named metal bein outermost, and the surface of the printing plate being treated with mercury so as to produce areas to which printing ink vvill not adhere.

Fig. 1 diagrammatically illustrates in section an improved plate according to this invention beforeetching.

Fig. 2 diagrammatically illustrates in section an improved plate according to this invnfonafter the resist has been locally app 1e Fig. 3 diagrammatically illustrates in section an improved plate according to this in-' vention after etching.;v

Fig. 4l diagrammatically illustrates Iin section an improved plate according to this invention after the initial electrodeposit has been effect-ed in the etched areas.

Fig. 5 diagrammatically illustrates in section an improved plate according to this invention after the alternate electrodeposits of copper and silver or silver and copper have l been applied tothe initial deposit, and

' Fig. 6 diagrammatically illustrates in section the nished plate ready for mercurizing.

The above figures are not strictly to scale and only serve the purpose of showing steps by which it is possible to produce the im-V 'proved plate on an iron base.

Referring to the drawings a is the iron base on which a layer a of copper anda layer of nickel have been electrodeposited, the thickness of the layer of nickel being about` one orone'and one halt one thousandths part of one inch `Whilst the layer of-coppcr may be of equal thickness or more or less is then etched \until the copper layer a is exposed and etching may be continued until aboutone ten thousandths part of an inch of the copper is removed; the total depth of each of the etched recesses d being about eleven or sixteen ten thousandths part of an inch.,

A layer e of copper, silver or gold is then electrodeposited into each of the recesses d so as to form a lining for such recesses and a protective covering for the copper a'. inasmuch as it has been found layer of copper or a metal having a greater affinity for mercury than copper is electrodeposited on to an electriodeposited copper surface, the last electrodeposited metal layer or the interface between the layers to some extent prevents mercury diffusing into the copper previously electrodeposited.

This prevention of diffusion' is probably due to the fact that as copper is electropositive to silver or gold the intimate molecular interchange at 'the interfaceduring the plating process produces actually or in effect an alloy of metals having this peculiar characteristic. (N

It has beem found that sults are obtained if the thickness of the layer e of copper, silver or gold is about one fifth of the total depth of a recess df or about twenty five one hundred thousandths part of an inch. Y

Each layere if of silver or gold has a layer f of co per electrodeposited thereon, said layer f being a proximately equal in thickness to that of t e layern e; but if the layer e is of copper then the layer f is of silver or gold.

As illustrated there are five layers in all of which g and It arev of vsilver or gold and i of copper the silver or gold and copper layers being alternately applied so as' to reduce the didusion to a minimum.

Obviously the invention is not limited to liveJ layers and any number of layers greater than two may be used provided that the last layer is of silver or` gold so as to provide a polished nongranular face on mercurization.

By the use of the alternate layers of silver or gold and copper or copper and silver or 'gold not only yis. it possible to obtain a large number of interfaces but it is also possible to arrange that veach of the recesses d are exactly filled up so as to produce a planographic printing surface.

Those skilled in electrodeposition of metal into recesses will recognize that it is impossible to prevent a ridge lo building up around each recess and this is removed by rubbing with polishing charcoal or very fine emery paper so that the printing surface is and remains perfectly planographic.

The non-printing [parts of the printing surface are mercurize by the application `of mercury in a metallic state for example, Aand that if a thin4 satisfactory refinally the resists c can be removed if so desired although this step is by no means absolutely necessary.

- l. A planographic printing plate having ink retaining areas and mercurial ink refusing areas, comprising a base plate, an electrodeposited layer of metal withwhich mercury can1 amalgamate, an electrodeposited layer of'a metal unaii'ected by mercury to which printing ink will adhere, a recess or recesses passing through said last named layer so as locally to expose the first named layer, and a highly polished mercurial amalgam in each recess.

2. A planographic printing plate having ink retaining areas and mercurial ink refusing areas, comprising a base plate, an electrodeposited layer of metal with which mercury can amalgamate, an electrodeposiited layer v"of a metal unaffected by mercury to which printing ink will adhere, a recess or recesses passing through said last named layer 'so as locally to expose the first named layer, and a plurality of alternately electrodeposited films of two metals in each recess one of said films forming a hard amalgam with mercury whilst the other film takes a'high polish when treated with mercury, a lilm of the last named metal beingl outermost;the surface of the printing plate being treated with mercury so as to produce mercurial areas to which printing ink will not adhere.

3. A-process for producing a planographic printing plate having ink retaining areas- Aand mercurial lnk refusing areas comprislng the electrolytic deposition of a layer of copper on to an iron base, the electrolytic deposition of a layer of nickel on to said layer of copper, the application of a local resist to the nickel layer to protectthe printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer ofa noble metal, the electrolytic deposition of alternate vthin layers of copper and a noble metal on to said thin layerso as to fill up said recess or recesses and externally present a surface of a noble metal, and the external application of mercury to such thin layers.

4. A process for producing a planographic printingpl'ilate having ink retaining areas and mclcurial' ink refusing areas comprising the electrolytic deposition of a` layer of copper on to an iron base, the electrolytic deposition of a layer ofnickle on to said copper layer, the application of a local resist to such nickel layer to protect ythe printing areas, lthe etching away of the unprotected parts of the nickel layer to expose the'copper` layer and form a recess or recesses, the elec-i on to said t the nickel and the copper of a thin layer of copper, the electrolytic deposition of alternate thin layers of a noble metal and copper on to said thin layer so as to fill up said recess or recesses and externally present ai surface ot'v a noble metal, and the external application'of mercury to such thin layers.

5. A process for producing a planographic printing plate havingi ink retaining lareas and mercurial ink refusing areas comprising the electrolytic deposition of a layer ot' copper one or one and one half one thousandths part of an inch in thickness on to an iron base, the .electrolytic deposition of a layer of nickel one or one and one half one thousandths part of an inch in thickness on to said copper layer, the application of a local resist to said nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and form a recess or recesses, the electrolytic deposition on the exposedparts of the nickel and the copper of a thin layer'ot a noble metal, the electrolytic deposition of alternate thin layers of copper and a noble metal on to said thin layer so as to fill up said recess or irecesses and externally present a surface oit' a noble metal, and the external application or mercury to such thin layers.

6. A process for producing a planographic printing plate having ink retaining areas and mercurial ink'refusing areas comprising the electrolytic deposition of a layer or' copper one or one and one half one thousandths part of an inch in thickness on to an iron base, the electrolytic deposition of alayer of nickel one or one and one halt one thousandths part of an inch in thickness on to said copper layer, the application of a local resist lto said nickel layer to protect the printing areas, the etching away et the un.- protected parts or the nickel layer to expose the copper layer and penetrating the copper layer or one ten thousandth part of an inch to form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the cop er ot a thin layer of a noble metal, the e ectrolytic deposition Iof alternate thin layers of copper "and a noble metal in layer so as to lill up said recess or recesses and externally present a surface of a noble metal and the external application of mercury to such thin layers.

-7. A process for producing a planographic printing plate having ink retainingareas and mercurial ink refusin areas comprising the electrolytlie deposit1on of a layer of copper one onone' and one half one thousandths part oan inch in thickness on to an iron base, the electrolytic deposition of a layer of nickel one or one and one half one f .thousandths part of an inch in thickness on to -said copper layer, the application of a local resist to said nickel layer to protect the expose the copper layer and penetrating thel copper layer for one ten tliousandth part of an inch to form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer of copper, the electrolytic deposition of alternate thin layers ci a noble metal andl copper on to said thin layer so as to lill up said recess or recesses and externally present a surface of a noble metal, and the external application of mercury to such thin layers.

8. A processfor producing a planographic printing plate having ink retaining areas and rnercurial ink refusing areas comprising the electrolytic deposition of a layer of copper' on to an iron base, the electrolytic depositionof a la er of nickel on to said layer ot copper, t e application lof a local resist to the nickel' layer to protect the printing areas, the etching away or the unprotected parts of the nickel layer to expose the copper layer and form a re ss or recesses, the electrolytic deposition o the exposed part-s of the nickel and the copper of a thin layer of silver, the'electrolytic deposition of alternate thin layers of copper and silver on to said thin layer so as to till up said recess or recesses and externally present a surface of silver, and the external application of mercury to such thin layers.

9. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising the electrolytic deposition of a layer ot copper on to an iron base,- the electrolytic deposition of a layer et nickel on to said copper layer, the application of a local resist to such nickellayer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and form a recess or recesses, the electrolytic deposition on the exposed parts' of the nickel and the copper of a thin-layer of copper, the electrolytic deposition oit alter-` lsilver, and the external application of niercury to such thin layers.

10. A process for producing a planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising the electrolytic deposition of a layer of copper one or-one and one half one thousandths part of an inch in thickness on to an iron base, the electrolytic depositionl or a layer of nickel one or one and one half one thousandths part of an inch in thickness on to said copper layer, the application of a local resist to said nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose llll) cesses, the electrolytic deposition on the exposedcparts of the nickel and the copper of l a surface of silver, and the external application of mercury to such thin layers.

11. A process for producing a i planographic printing plate having ink retaining areas and mercurial ink refusing areas comprising' the electrolytic deposition of a layer of copper one or one and one half one thousa-ndths part of an inch in thickness on to an iron base, the electrolytic deposition of a layer of nickel one or one and one half one thousandths part of an inchin thickness on to said copper layer, the application of a local resistv to saidnickel layer to protect the printing aneas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and penetrating the copper layer for one ten thousandth part of an inch to form a recess'or recesses, the electrolytic deposition'on the exposed parts of `the nickel and the copper of a thin layer ofsilver, the electrolytic deposition of alter-- nav-*e thin layers of copperand silver-on to i thin layer so as to Vfill up said recess or recesses and externally present a surface of silver, and the external application of mercury to such thin layers.

l2.l A process for producing a planographic printing plate having inkretaining areas and rinercurial ink refusing areas comprising the elect'rolytic deposition of a layer of copper one or one and one haltl one thousandths part of an inch in thickness on to an 1ron base base, the electrolytic deposition of a layer of nickel one or one and one half one thousandths part of an inch in thickness on to said copper layer, the application of a local resist. to said nickel layer to protect the printing areas, the etching away of the unprotected parts of the nickel layer to expose the copper layer and penetrating the copper layer for one ten thousandth part of an inch to form a recess or recesses, the electrolytic deposition on the exposed parts of the nickel and the copper of a thin layer of copper, the electrolytic deposition of alternate thin layers of silver and copper on to said thin layer so as to fill up said recess or recesses and externally present a surface of silver, and the external application of mercury to such thin layers'.

ARTHUR RONALD TRIsT. 

